Manufacturing method using a proximity latch mechanism in an impact rebound crash stop for an outside disk ramp loading disk drive

ABSTRACT

The invention includes methods of making actuator arms, actuators and disk drives using an impact rebound crash stop pivoting about a pivot between the top and bottom yoke of an actuator magnet assembly. The impact rebound crash stop includes a latch bias tab magnetically attracted to the voice coil magnet when it is near. The invention further includes a proximity latch allowing the actuator to stay on the ramp when not in use. The invention includes actuator arms embedding part of the magnetic proximity latch.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This is a divisional application of U.S. patent application Ser.No. 10/117,518, filed Apr. 4, 2002, entitled: A Proximity LatchMechanism Using an Impact Rebound Crash Stop for an Outside Disk RampLoading Disk Drive.

TECHNICAL FIELD

[0002] This invention relates to manufacturing disk drive components anddisk drives with novel latch mechanisms used in parking read-write headsoutside the disk media surface(s).

BACKGROUND ART

[0003] Disk drives are an important data storage technology based onseveral crucial components including disk media surfaces and read-writeheads. When in operation, rotation of disk media surfaces, with respectto the read-write heads, causes each read-write head to float a smalldistance off the disk media surface it accesses. However, for a varietyof reasons, disk media surfaces frequently stop rotating when not inoperation for awhile.

[0004] When the disk media surface is not rotating with respect to theread-write head, mechanical vibrations acting upon the disk drive cancause the read-write head to collide with the disk media surface, unlessthey are separated.

[0005] This separation is often referred to as “parking” the read-writeheads. Parking the read-write heads minimizes the possibility ofdamaging the disk media surfaces and/or the read-write heads due tothese mechanical collisions. Often such parking mechanisms include aramp on which the head slider(s) are “parked” and a latch mechanism. Thepurpose of the latch mechanism is to minimize the chance that theactuator will accidentally leave the parking ramp outside the disk mediasurface and potentially damage the disk media surface(s).

[0006]FIG. 1A illustrates a typical prior art high capacity disk drive10 including actuator arm 30 with voice coil 32, actuator axis 40,suspension or head arms 50-58 with slider/head unit 60 placed among thedisks.

[0007]FIG. 1B illustrates a typical prior art high capacity disk drive10 with actuator 20, actuator arm 30 with voice coil 32, actuator axis40, head arms 50-56 and slider/head units 60-66 with the disks removed.

[0008] Since the 1980's, high capacity disk drives 10 have used voicecoil actuators 20-66 to position their read/write heads over specifictracks. The heads are mounted on head sliders 60-66, which float a smalldistance off the disk drive surface when in operation. Often there isone head per head slider for a given disk drive surface. There areusually multiple heads in a single disk drive, but for economic reasons,usually only one voice coil actuator.

[0009] Voice coil actuators are further composed of a fixed magnetactuator 20 interacting with a time varying electromagnetic fieldinduced by voice coil 32 to provide a lever action via actuator axis 40.The lever action acts to move head arms 50-56 positioning head sliderunits 60-66 over specific tracks with remarkable speed and accuracy.Actuator arms 30 are often considered to include voice coil 32, actuatoraxis 40, head arms 50-56 and head sliders 60-66. Note that actuator arms30 may have as few as a single head arm 50. Note also that a single headarm 52 may connect with two head sliders 62 and 64.

[0010] While there are many forms of mechanical impact upon a diskdrive, only rotary shock in actuator 30's plane of motion can bring theread-write heads into collision with disk media surfaces once theread-write heads are parked. These rotary shocks will be describedherein based upon a view defining clockwise and counterclockwiserotations with respect to the disk drive base, with a parking zonelocated to the right of the disk media surfaces as viewed from above thedisk base. As will be apparent to one of skill in the art, it is just aspossible for a disk drive to use a parking zone on the left of the diskmedia surfaces. While this is most certainly possible, the discussionhereafter will focus on a parking zone to the right to clarify thediscussion. Such a clarification is not meant to limit the scope of theclaims.

[0011]FIG. 1C illustrates a magnetic latch affixed to an actuator arm 30of the prior art.

[0012] A magnet is affixed to the tail end of the voice coil 32 region,which when near a second magnet located in either the top yoke or bottomyolk of the fixed magnet region 20, will tend to attract actuator 30 toa parking site often inside the disk media. Magnetic latches are usedwith Crash Start Stop (CSS) designs.

[0013] While they have been put into production in severalcircumstances, they place additional requirements on the voice coilactuators. This kind of latch requires additional actuator torque toexit from the parking zone. Further, these latches require sophisticatedactuator speed control. Inside disk parking zones also tend to heat theread-write heads more. The read-write heads tend to suffer more frequentmechanical collisions with the disk surface.

[0014] The outside disk surface approach to parking read-write headsparks the read-write head or heads on a ramp outside the disk surface,removing and/or minimizing the possibility for contact when the disk isnot in operation. Latch mechanisms provide at least some assurance thatthe actuator will remain parked with head sliders on the ramp even aftermechanical shocks to the disk drive.

[0015]FIGS. 2A to 2C illustrate the operation of a single lever inertiallatch as found in the prior art.

[0016]FIG. 2A illustrates the prior art single level inertial latchmechanism including latch arm 100 pivoting about 102 and including latchhook 104, mechanically fitting with actuator catch mechanism 106, aswell as latch stop 110, and crash stop 90, with the latch mechanism atrest.

[0017] Note that actuator 30 abuts crash stop 90 and that inertial latcharm 100 abuts latch stop 110 when the single-lever inertial latch is atrest. Slider 60 is in position on parking ramp 120.

[0018]FIG. 2B illustrates the prior art single level inertial latchduring a clockwise acceleration of actuator 30.

[0019] In a clockwise acceleration, actuator 30 moves away from crashstop 90 and actuator catch mechanism 106 engages with inertial latchcatch mechanism 104.

[0020]FIG. 2C illustrates the prior art single level inertial latchduring a counterclockwise acceleration of the actuator.

[0021] In a counterclockwise acceleration 130, the latch may fail if theactuator 30 rebounds 132 from its crash stop 90.

[0022]FIG. 3A illustrates a prior art example of a dual-lever inertiallatch at rest.

[0023] When at rest, a magnet or spring, (which are not shown), biasesthe small latch arm 142 clockwise, holding the latch 144-152 open.

[0024]FIG. 3B illustrates a prior art example of a dual-lever inertiallatch during a clockwise rotational acceleration of actuator 30.

[0025]FIG. 3C illustrates a prior art example of a dual-lever inertiallatch during a counterclockwise rotational acceleration of actuator 30.

[0026] The large latch arm 140 rotates in opposite directions during theclockwise and counterclockwise motions of actuator arm 30 of FIG. 3B and3C, respectively. Motion of large latch arm 140 in either directioncauses the small arm 142 to rotate counterclockwise to the closeposition. This dual lever action prevents a rebound of actuator arm 30off the crash stop 90 from escaping the latched condition.

SUMMARY OF THE INVENTION

[0027] The invention includes an impact rebound crash stop pivotingabout a pivot 218 between the top and bottom yoke of an actuator magnetassembly 20. The impact rebound crash stop includes a latch bias tab 210magnetically attracted to is the voice coil magnet 32 when near. Themagnet attraction rigidly moves a crash stop 216 about pivot 218. Thismotion engages the crash stop 216 with crash stop site 226, as well aspusher 212 with pusher site 224. Pusher site 214 and crash stop site 226are both on the actuator 30 fantail.

[0028] The impact rebound crash stop uses an impact reboundbidirectional inertial latch and is preferably made of at least oneplastic with low elastic coefficient and a magnetically attractive latchbias tab 210. The plastic is preferably essentially rigid.

[0029] The invention further includes a proximity latch for an outsidedisk, ramp loading disk drive allowing the actuator to stay on the rampwhen not in use. The proximity latch includes two small magnets 220bonded to the top and bottom yoke of the voice coil magnet assembly 20and the impact rebound crash stop.

[0030] The proximity latch mechanism attracts a magnetically attractivecomponent molded into the actuator fantail. The attraction is toward thecrash stop. The two magnets and magnetically attractive componentattract each other, but do not make contact.

[0031] The proximity latch, together with the impact rebound crash stop,provide an outside disk ramp loading disk drive with a very reliable,non-contact break free latch while maintaining a high resistance toaccidental latch release during rotary shock conditions. The proximitylatch mechanism achieves this without using any inertial latchmechanism, eliminating the extra travel allowance required by an impactrebound inertial latch mechanism.

[0032] The invention includes the actuator arm 30 embedding themagnetically attractive component 222 in the actuator fantail. Theinvention further includes an actuator 20-66 containing the proximitylatch mechanism with the magnetically attractive component 222 andpusher stop 224 in the actuator fantail and crash stop 210-218 mountedthrough its pivot 218 to the top yoke 224 and bottom yoke 222 of theactuator magnet assembly 20.

[0033] The invention includes the making of these actuators with theircrash stop and proximity latch mechanisms, as well as the making of diskdrives using these actuators, and the disk drives themselves.

[0034] The invention includes the method of parking an actuator throughthe operation of an internal crash stop and the operation of theinternal proximity latch. The invention also includes the method ofparking a disk drive using the method of parking the actuator.

[0035] These and other advantages of the present invention will becomeapparent upon reading the following detailed descriptions and studyingthe various figures of the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0036]FIG. 1A illustrates a typical prior art high capacity disk drive10 including actuator arm 30 with voice coil 32, actuator axis 40,suspension or head arms 50-58 with slider/head unit 60 placed among thedisks;

[0037]FIG. 1B illustrates a typical prior art high capacity disk drive10 with actuator 20, actuator arm 30 with voice coil 32, actuator axis40, head arms 50-56 and slider/head units 60-66 with the disks removed;

[0038]FIG. 1C illustrates a magnetic latch affixed to an actuator arm 30of the prior art;

[0039]FIG. 2A illustrates the prior art single level inertial latchmechanism including latch arm 100 pivoting about 102 and including latchhook 104, mechanically fitting with actuator catch mechanism 106, aswell as latch stop 110, and crash stop 90, with the latch mechanism atrest;

[0040]FIG. 2B illustrates the prior art single level inertial latchduring a clockwise acceleration of actuator 30;

[0041]FIG. 2C illustrates the prior art single level inertial latchduring a counterclockwise acceleration of the actuator;

[0042]FIG. 3A illustrates a prior art example of a dual-lever inertiallatch at rest;

[0043]FIG. 3B illustrates a prior art example of a dual-lever inertiallatch during a clockwise rotational acceleration of actuator 30;

[0044]FIG. 3C illustrates a prior art example of a dual-lever inertiallatch during a counterclockwise rotational acceleration of actuator 30;

[0045]FIG. 4 illustrates an impact rebound type bidirectional inertiallatch;

[0046]FIG. 5A illustrates the proximity latch mechanism in the openposition;

[0047]FIG. 5B illustrates the proximity latch mechanism in the closedposition;

[0048]FIG. 6A illustrates a side view of the proximity latch mechanismas housed in the voice coil magnet assembly; and

[0049]FIG. 6B illustrates a perspective view of the proximity latchmechanism.

DETAILED DESCRIPTION OF THE INVENTION

[0050] A proximity latch for an outside disk ramp loading disk drivesallows the actuator to stay on the ramp when not in use (see FIGS. 5A to6B).

[0051]FIG. 4 illustrates an impact rebound type bidirectional inertiallatch.

[0052] The inertial latch rests in an open position due to a light biastorque applied by the magnetic attraction between the voice coil magnet32 and the balance steel 200 when there is no externally inducedrotational acceleration acting upon actuator arm 30.

[0053] Actuator arm 30 and the latch assembly 102-104-202 arerotationally balanced. During clockwise rotational acceleration of thedisk drive, the latch 102-104 rotates in the counterclockwise directionwith respect to the base. This latch motion causes the latch hook 104 toengage the barb 106 on the actuator 30 tail. During counterclockwiserotational acceleration of the disk drive, actuator arm 30 rebounds fromits crash stop 90 and the latch 202-102-104 also rebounds in theclockwise direction with respect to the base, due to the actuator tailtouching the rebound part 202 of the latch. This latch motion causes thelatch hook 104 to engage the barb 104 on the actuator 30 tail.

[0054]FIG. 5A illustrates the proximity latch mechanism in the openposition.

[0055]FIG. 5B illustrates the proximity latch mechanism in the closedposition.

[0056]FIG. 6A illustrates a side view of the proximity latch mechanismas housed in the voice coil magnet assembly.

[0057]FIG. 6B illustrates a perspective view of the proximity latchmechanism.

[0058] The proximity latch includes two small magnets 220 bonded to thetop yoke 22 and bottom yoke 24 of the actuator assembly 20 and an impactrebound crash stop 216. The impact rebound crash stop 216 uses an impactrebound big directional inertial latch 210-218. The impact reboundbidirectional latch includes pusher 212, latch pivot 218 and latch biastab 210.

[0059] The proximity latch mechanism attracts a magnetically attractivecomponent 222 molded into the actuator fantail toward the two smallmagnets 220. The actuator fantail is further formed of a pusher stop 224and a crash stop site 226. The attraction is toward the pusher 212. Notethat the small magnets 220 are preferably magnetically aligned so thattheir North poles point in essentially the same direction.

[0060] The two small magnets 220 and magnetically attractive component222 attract each other, but do not make contact. However, as the twosmall magnets 220 and the magnetically attractive component 222 approacheach other, pusher stop 224 engages pusher 210, rotating the proximitylatch mechanism 210-218 about latch pivot 218 to engage crash stop 216and crash stop site 226.

[0061] The magnetically attractive component 222 is preferably made of amagnetically attractive form of steel, preferably number 430.

[0062] Note that the proximity latch mechanism illustrated in FIGS. 5Aand 5B does not use an impact rebound inertial latching mechanism. Thiseliminates the extra travel allowance required in all the designsillustrated by FIGS. 1C to 4.

[0063] The impact rebound crash stop 216 halts the actuator 30 at acontact point illustrated in FIG. 5B through engagement with crash stopsite 226 on actuator arm 30.

[0064] The magnetic force between the magnetically attractive actuatorcomponent 222 and the two non-contact magnets 220, provide a torque uponthe actuator. This magnetic force is preferably between 4.8 and 6.0Newton-meter{circumflex over ( )}2. This preferred magnetic forcesupports high rotary shock performance in the clockwise direction. Theimpact rebound crash stop 216 is used to keep the actuator 30 fromrebounding during counterclockwise rotary shocks. The impact reboundcrash stop 216 is built into the voice coil magnet assembly as shown inFIG. 6B.

[0065] When the actuator approaches the impact rebound crash stop, themagnetic latching mechanism engages and helps the actuator to movefaster into the crash stop. The magnetic latching mechanism includes themagnetic attraction between the two small magnets and magneticallyattractive component molded into the actuator. The two small magnets areplaced on the top and bottom yokes of the voice coil magnet assemblyexactly so that the actuator is maintained at a parking “home” where theimpact rebound crash stop is located. As the magnetically attractivecomponent of the actuator slowly approaches the flux generated by thesetwo small magnets, the actuator pushes upon the impact rebound crashstop. The impact rebound crash stop is rotated clockwise until theimpact rebound crash stop touches the actuator by its latch arm at thecrash stop.

[0066] The proximity latch mechanism helps a disk drive resistrelatively high rotary shock in the clockwise direction with respect tothe disk drive base. This resistance depends upon the magneticattractive force between the two small magnets and the magneticallyattractive component molded into the actuator.

[0067] The impact rebound crash stop helps increase rotary shockperformance in the counterclockwise direction with respect to the diskdrive base. The impact response crash stop is preferably made fromplastic, preferably from an ultem plastic material. The actuator fantail is preferably includes a plastic overmold made of vectra.

[0068] The elastic coefficient between the plastic impact response crashstop and the plastic overmold actuator fantail is less than one,preferably about 0.6. The elastic coefficient being less than onecontributes to very minimal rebound effect from impact between theactuator fantail and the impact rebound crash stop. The loss of highenergy during the impact also significantly reduces the chance of suddenimpact rebound motion. This reduction in the chance of sudden impactrebound motion, combined with the reduced energy of any sudden impactrebound motion, both contribute to high rotary shock resistance in thecounterclockwise direction with respect to the disk drive base.

[0069] The latch bias tab 210 is molded into the latch mechanism andsupports the latch opening its arm automatically when the actuator iscontrolled to move out in a desirable speed. The latch opens its armbased upon the attractive force generated on the latch bias tab 210 bythe voice coil magnet 32. The latch bias tab 210 is preferably composedof a magnetically attractive steel compound preferably SUS 430 steel.

[0070] The invention secures read-write head parking through rotationalshocks of 25,000 to 30,000 radians/sec{circumflex over ( )}2 of up totwo milliseconds duration. Note that the contemporary industry standardis support for up to 20,000 radians/sec{circumflex over ( )}2.

[0071] Depending upon the small magnets, the performance can protectread-write head parking under even more severe conditions. The smallmagnets preferably have magnetic strengths of 48 MGO and are preferably1.5 millimeters thick and 3 millimeters by 4 millimeters wide.

[0072] The preceding embodiments have been provided by way of exampleand are not meant to constrain the scope of the following claims.

1. A method of making an actuator, comprising the steps of: attaching arigid body by a pivot between a top yoke and a bottom yoke coupling animpact rebound crash stop to an actuator magnet assembly to at leastpartly create a proximity latch mechanism; and attaching an actuator armcoupled with a voice coil magnet between said top yoke and said bottomyoke to enable said voice coil magnet moving near said impact reboundcrash stop to at least partially create said proximity latch mechanism;wherein said actuator magnetic assembly is coupled with an yoke assemblycomprising said top yoke and said bottom yoke; wherein said proximitylatch mechanism comprises: said pivot, a latch bias tab, a pusher, andsaid impact rebound crash stop.
 2. The method of claim 1, wherein saidrigid body contains said pivot.
 3. The method of claim 1, wherein whensaid voice coil magnet is near said impact rebound crash stop, saidproximity latch mechanism pivots bringing said pusher face into arotational path of a pusher stop leading to said pusher engaging saidpusher stop; wherein said actuator arm includes said pusher stop.
 4. Themethod of claim 3, wherein when said pusher face engages said pusherstop, said proximity latch mechanism pivots engaging said impact reboundcrash stop and a crash stop site included in said actuator arm.
 5. Themethod of claim 4, wherein when said impact rebound crash stop engagessaid crash stop site and a first voltage is applied to said voice coilmagnet, said voice coil magnet magnetically acts against said actuatormagnet assembly repelling said crash stop site from said impact reboundcrash stop.
 6. The method of claim 1, wherein said actuator arm includessaid voice coil magnet and an actuator fantail; wherein said actuatorfantail comprises a pusher stop face and a crash stop site.
 7. Themethod of claim 6, further comprising the step of: rigidly attaching anovermold to said actuator fantail to create said actuator arm; whereinsaid overmold contains said pusher stop face and said crash stop site.8. The method of claim 7, further comprising the step of: creating saidproximity latch with a magnetically attractive component in saidactuator fantail.
 9. The method of claim 8, wherein when said actuatorfantail is near small magnets in said proximity latch mechanism, saidmagnetically attractive component and said small magnets attract eachother, moving said actuator fantail near said impact rebound crash stop.10. The method of claim 9, wherein the step creating said proximitylatch is further comprised of the steps of: affixing said small magnetsto said yoke assembly; and using said actuator fantail in said actuatorarm.
 11. The method of claim 10, wherein said proximity latch furtherincludes two of said small magnets; wherein the step affixing saidmagnet is further comprised of the steps of: affixing each of said smallmagnets to said yoke assembly so that said small magnets essentiallyshare the same North pole.
 12. The method of claim 11, wherein when saidactuator fantail is near said small magnets, said magneticallyattractive component and said small magnets attract each other, movingsaid actuator fantail near said impact rebound crash stop.
 13. Themethod of claim 10, wherein said actuator fantail further comprises anovermold containing said pusher stop face, said crashstop site, and saidmagnetically attractive component; and wherein the step using saidfantail is further comprised of the step of using said overmold rigidlyattached to said actuator arm.
 14. The method of making a disk drive,comprising the step of using said actuator of claim
 1. 15. A method ofmaking an actuator, comprising the steps of: attaching a rigid body by apivot between a top yoke and a bottom yoke coupling an impact reboundcrash stop to an actuator magnet assembly to at least partly create aproximity latch mechanism; and attaching said actuator coupled with avoice coil magnet between said bottom yoke and said top yoke to enablesaid voice coil magnet moving near said impact rebound crash stop to atleast partially create said proximity latch mechanism; and creating aproximity latch with said impact rebound crash stop using a magneticallyattractive component in an actuator fantail coupled with said voice coilmagnet; wherein said proximity latch mechanism comprises: said pivot, alatch bias tab, a pusher face, and said impact rebound crash stop. 16.The method of claim 15, wherein said actuator fantail comprises saidpusher stop face and said crash stop site.
 17. The method of claim 16,wherein when said actuator fantail is near said impact rebound crashstop, said proximity latch mechanism pivots bringing said pusher faceinto a rotational path of a pusher stop leading to said pusher faceengaging said pusher stop; wherein said actuator arm includes saidpusher stop.
 18. The method of claim 17, wherein when said pusher faceengages said pusher stop, said impact rebound crash stop pivots engagingsaid impact rebound crash stop and a crash stop site included in saidactuator arm.
 19. The method of claim 18, wherein when said impactrebound crash stop engages said crash stop site and a first voltage isapplied to said voice coil magnet, said voice coil magnet magneticallyacts against said actuator magnet assembly repelling said crash stopsite from said impact rebound crash stop.
 20. The method of claim 16,wherein when said actuator fantail is near said small magnet, saidmagnetically attractive component and said small magnet attract eachother, moving said actuator fantail near said impact rebound crash stop.21. The method of claim 15, wherein said proximity latch includes smallmagnets affixed to said yoke assembly so that said small magnets sharethe same North Pole; wherein the step creating said proximity is furthercomprised of the step of: using said actuator fantail interacting withsaid small magnets.
 22. The method of claim 21, wherein when saidactuator fantail is near said small magnets, said magneticallyattractive component and said small magnets attract each other, movingsaid actuator fantail near said impact rebound crash stop.
 23. Themethod of claim 15, wherein said actuator fantail further comprises anovermold containing a pusher site, a crash stop site, and saidmagnetically attractive component; and wherein the step using saidfantail is further comprised of the step of: using said overmold rigidlyattached to said actuator arm.
 24. A method of making a disk-drive,comprising the step of using said actuator of claim 15.